I'm wondering, in a clustered SQL2012 environment you can put your tempdb on a local disk for performance improvements. Is it possible to put tempdb from multiple instances on the same disk, or will something prevent this (all instances points it tempdb to t:\data\instancename\tempdb\, where t:\ is a local disk)?

I can't really see any technical problems with this, but unfortunately I don't have the possibility to try this myself, and google didn't help me.

It's a windows failover cluster (WSFC) I'm thinking about, with two or more instances.

I would still consider this as an approach, as you might get this drive hammered down by one of the instances, which will ultimately affect the rest of the instances, using the same drive for it's tempdb (if they are sharing the same active note, of course). I guess you already have that in mind, but still - I need to mention it :)

I didn't verify the statement that this IS available in SQL 2012, but if it turns out to not be I do know there has been an (unsupported) workaround for this for many years. It has been used by many installations to do just what you are doing.

Msg 5184, Level 16, State 2, Line 1Cannot use file 'q:\testDB.mdf' for clustered server. Only formatted files on which the cluster resource of the server has a dependency can be used. Either the disk resource containing the file is not present in the cluster group or the cluster resource of the Sql Server does not have a dependency on it.Msg 1802, Level 16, State 1, Line 1CREATE DATABASE failed. Some file names listed could not be created. Check related errors.

We are talking about tempdb of a clustered SQL Server 2012 instance and since that release Microsoft supports tempdb on a local drive. For detailed instruction, you can check here:http://www.mssqltips.com/sqlservertip/2817/sql-server-2012-cluster-with-tempdb-on-local-disk/